Bicycle Power - How many Watts can you produce?

Clothes slow Lance down

Clothes slow Lance down

I love watching the Tour de France each summer and I enjoy watching the coverage and seeing the cyclist's wattage as they race away from the peloton or climb the Alps. By understanding how much power a person can produce, it should give you a good frame of reference on the scale of electric power production!

As I watch the Tour they occasionally display a rider's instantaneous power output on the screen.  They are able to do this because the cyclist has a power meter on their bike and this transmits data to the broadcasting network.  So just like the TED can monitor my home's power consumption, the bicycle power meter measures a cyclist's power production.  This power usually ranges anywhere between 250 Watts if they are just cruising along with the pack, or 400-500 Watts if they are pushing hard up a steep climb.  To see another example of a cyclist's power watch this Olympic cyclist power a toaster

A Watt is an instantaneous measure of power and is a product of force and speed.  In electrical terms, the force is Voltage and speed is current (Amps); therefore, electrical power is Voltage * Current. For a cyclist, the force is how hard he pushes on the pedals and the speed is how fast he turns the crank (rpm).  The combination of these two things results in the cyclist's power output, which is usually expressed in Watts.   Remember, you need force and speed to get power.  If you go to spin class you may see those cyclists spinning the crank very fast, but their power may not be that high if they dont have a lot of resistance - which requires more force by the cyclist - on the wheel.  For more on this topic, see the great FAQ section that has been put together on this page dedicated to bicycle power generation.

The International Cycling Union (UCI) maintains records for the Hour Record, which is an ongoing contest to see who can ride the farthest (measured in km) in one hour.  To get a good estimate of the maximum energy a person can produce (these are elite athletes after all), we'll figure out the average wattage of someone competing for the Hour Record, and since it lasts an hour, this average wattage will be the total energy the rider expended over that hour.  Therefore, the energy they expend over the time they compete can be presented in Watt-hours.

The current record holder for the Hour Record is ex-pro cyclist and 2012 Tour de France winner Bradley Wiggins.  In his book on his hour record chase, My Hour, Wiggins discusses how air pressure affects speed.  Air pressure is a force acting against the cyclist, so the cyclist has to put more force on the crank to overcome it.  If it is desired to maintain a constant speed, and air pressure increases, force will also have to increase to maintain the same speed (from Newton's third law: for every action there is an equal and opposite reaction). Wiggins states:

For every 20 millibars the air pressure goes up, your lap time increases by 0.1 sec.  For example, in Manchester I had been travelling at 55 km/h in training, which roughly equated to Tony Rominger's second record; on days when the pressure was 990 millibars I'd do 30 minutes at 55 km/h putting out 410 watts.  My aerobic threshold is between 420 and 460 watts, so putting out that power I could have kept going at that pace for an hour and a half.  That was why we started working towards the 55 km target.  In London on the day, however, because the air pressure was 1,036 millibars, to cover 54.5 km in the hour I had to average 440 watts; to stick to that 55 km/h schedule would have taken 460 watts, which I couldn't sustain.  The pace I went depended on the pressure on the day. 

Wiggins did end up doing about 440 Watts as his final distance was 54.526 km!  If Wiggins' bike were attached to a bicycle generator and it was super efficient, Wiggins would have been generating enough power to light up 7 60-Watt light bulbs!  Since I pay about 10 cents/kWh, if I were to pay Wiggins for the energy he produced over the hour he was pedaling he would have almost earned a whole nickel (440 Watts • 1 hour = 440 Watt-hours = .44 kWh)!

Hour-watts-power-outputThe cycling blogger Alex Simmons has a great article on the current Masters Men (35-39) Hour Record holder Jayson Austin and his power output over his attempt at the Master's record in 2009.  Jayson's average power output was 302 Watts over the hour he rode.  The year before Jayson tried to go for the record but was only able to produce an average of 241 Watts (he wasnt feeling too well, so you can see his power output decline the longer he rode).  The graph of the two attempts can be seen at the right.

As you can see, the best human efforts at producing power over the course of an hour on a bicycle are around 300-400 Watts.  To put this in perspective, when my AC is running full blast my house can consume about 4,000 Watts or 4 kW.  I would need over 10 of the best cyclists in the world attached to bicycle generators to power my house when it is consuming this much power!  While this doesn't diminish the effort of the cyclists, it does demonstrate that powering our future by pedal power doesn't look like an option, unless they want to work for nickels.....

November 2009 issue of Bicycling magazine has an excellent article on human powered bicycle generators that I highly recommend.  As someone who is passionate about renewable energy and cycling, I get very excited reading this stuff.  The article mentions two companies that are trying to retrofit gym equipment and spin classes to produce and display cyclists power output.  ReRev is retrofitting gym equipment to produce clean energy and The Green Revolution is doing something very similar and targeting spin classes.  I've wanted something like this in my gym for awhile.  I'm not a big fan of spin class currently because there is no feedback on how I'm performing and improving.  These companies can provide valuable feedback on your power output AND produce clean, renewable energy for the grid.  This is win-win stuff.

BTW, we're working on a new site all about cycling power output and comparisons.  Check it out. crankwatts - bicycle power comparisons

Check out this related products on Amazon:



If you're interested in generating electricity from a bicycle check out our post on Human Bicycle Power Generation.

Going further on the topic of human bicycle power output, here's our post on how many cyclists it would take to replace a nuclear power plant!

Check out this cool video from SportsArt Fitness introducing the new ECOFIT Networking System for their electricity-producing Green System.

Associated Press - Oregon gym installs power generating equipment

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Hi I just read your post.. Wondering how many people aroud the world are riding bicycles in the gyms and fitness centers? Any idea how much they might be producing altogether?
ckmapawatt's picture
Good question...I'm really not sure. Unfortunately though it wouldn't be practical or cost effective to take advantage of the power they generate.
It's not cost effective when you bring money into the equation, how about get the unemployed (which I am) to do it, but have them charging batteries for electric vehicles, get EVERYONE driving electric vehicles, pay the unemployed their benefits with no hoops to jump through, end societies reliance on a finite fossil fuel, which will only increase in cost and thus make EVERYTHING else more expensive. If you're driving an electric car, running low on charge, far from home and a full charge takes about 6 hours, pop into nearest bike battery charging station and swap your almost flat battery for a fully charged one. The money side of it is just a bunch of numbers at the end of the day, this could be of real benefit to society, harnessing a surplus resource (people) to solve a global problem. I wouldn't be pedalling to make a rich man richer, I'm pedalling to save the environment.
ckmapawatt's picture
I could help you run the numbers, but I just dont think it would work. Think about it this way. Take me for instance: I weight about 170 lbs, and I can ride as hard as I can at 20 mph for about 3 hours. A car weighs about 10 times that. So doing the quick math, I could create enough energy that may allow a car to go 2 mph for 3 hours, or 20 mph for 18 minutes. Unfortunately, humans just can't expend the energy that fossil fuels can.
Just stumbled upon this discussion, Interestingly, while the human body may produce these 300-400 Watt's over an hour it will also produce at least 4-fold that amount of energy in heat (20% efficiency). That energy is set free as heat and water vapor (evaporative heat loss through sweat and breathing). If you use 10 cyclists to power your AC they will overheat quickly and condensation will start running down the walls; you will need a 4 times larger auxiliary AC to keep them pedaling. In human biology the output of the human body is expressed as the total amount of energy produced, which is the sum of external work (the bike) plus heat produced. So Lance's body actually produces about 5 times more energy then what the bike registers! Best wishes, Paul.
This is never going to be our way out of any energy problems.... There is enough oil in the ground in ND for the next 300 years. And, with the earth naturally producing it - constantly - why not grab some of it before Akbar claims the land?
Oddly enough, this information has helped me A LOT in writing my novel. Thank you, Chris, I will mention you in my acknowledgments if I ever get published! :)
I enjoyed the read. Thanks for the info. I really thought people would be able to produce more power. I have new respect for these little motors all around me now. My lawnmower is 10X more powerful than an athlete cyclist and probably 30X more powerful than me, and it can run all day given enough fuel. I probably couldn't even keep up with my oscillating desk fan in an all day power output contest
ckmapawatt's picture
What's the novel about?
It's about a bunch of college who get lost and scattered through time and are trying to find their way back to each other. They end up using a scavenger hunt thing to try and get back together. But if you need your barely charged laptop to work in order to find out a clue while stuck in 1906....Well, you might not have enough wattage in your wall to power up a computer. This would be an interesting alternative! Sorry it took so long for me to respond. And thanks again!


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